1. Field of the Invention
The present invention relates to an antenna device mounted, for example, on a car and having a plurality of antenna units. More particularly, the invention relates to an antenna device in which a variety of antenna units are structurally and electrically uniformalized and aggregated together.
2. Prior Art
FIG. 9 is a perspective view illustrating, in a disassembled manner, a conventional antenna device disclosed in, for example, Japanese Unexamined Patent Publication (Kokai) No. 169248/1997 together with the peripheral structure thereof in the case where the antenna device to be mounted on a car is incorporated in a roof module.
In FIG. 9, an antenna unit 2 and a control unit 3 are incorporated as a unitary structure in a molded substrate 1 that constitutes a roof module A of an automobile (not shown), and a circuit conductor 4 is arranged therein.
The circuit conductor 4 electrically connects the antenna unit 2 and the control unit 3 together, and guides the signals received by the antenna unit 2 to an external circuit device.
A room mirror 5 and a sun visor 6 constitute the roof module A together with the molded substrate 1.
The antenna unit 2 is constituted by, for example, the one for navigation.
Though not diagramed here, another antenna unit for, for example, an automatic fee receiving system (hereinafter abbreviated as "ETC") is incorporated in another module mounted on the car.
According to the conventional antenna device as shown in FIG. 9, the mounting position has been limited to be, for example, in the roof module. It is not, therefore, allowed to arbitrarily select and install an antenna unit required by a user.
That is, the roof module A of FIG. 9 incorporates the antenna unit 2 for receiving radio waves or navigation waves only. In order to incorporate an antenna unit for other functions such as of TV, therefore, a separate module must be mounted on the car.
In general, furthermore, the shape of the roof module differs depending upon the vehicles. Therefore, it is not allowed to, or it cannot be expected to, easily incorporate a plurality of antenna units, since it is difficult to standardize or uniformalize the roof modules among the manufacturers or among the models of the cars.